The “Best Catalyst” for Water Oxidation Depends on the Oxidation Method Employed: A Case Study of Manganese Oxides

2015 ◽  
Vol 137 (26) ◽  
pp. 8384-8387 ◽  
Author(s):  
Ravi Pokhrel ◽  
McKenna K. Goetz ◽  
Sarah E. Shaner ◽  
Xiaoxia Wu ◽  
Shannon S. Stahl
Keyword(s):  
Water Oxidation ◽  
Manganese Oxides ◽  
Oxidation Method

scholarly journals Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation

2013 ◽  
Vol 110 (22) ◽  
pp. 8801-8806 ◽  
Author(s):  
N. Birkner ◽  
S. Nayeri ◽  
B. Pashaei ◽  
M. M. Najafpour ◽  
W. H. Casey ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Water Oxidation ◽  
Manganese Oxides

Nanostructured Manganese Oxides as Highly Active Water Oxidation Catalysts: A Boost from Manganese Precursor Chemistry

ChemSusChem ◽  
2014 ◽  
Vol 7 (8) ◽  
pp. 2202-2211 ◽  
Author(s):  
Prashanth W. Menezes ◽  
Arindam Indra ◽  
Patrick Littlewood ◽  
Michael Schwarze ◽  
Caren Göbel ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Manganese Oxides ◽  
Precursor Chemistry ◽  
Oxidation Catalysts ◽  
Highly Active ◽  
Manganese Precursor

scholarly journals Nano-sized manganese oxides as biomimetic catalysts for water oxidation in artificial photosynthesis: a review

2012 ◽  
Vol 9 (75) ◽  
pp. 2383-2395 ◽  
Author(s):  
Mohammad Mahdi Najafpour ◽  
Fahimeh Rahimi ◽  
Eva-Mari Aro ◽  
Choon-Hwan Lee ◽  
Suleyman I. Allakhverdiev
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Water Oxidation ◽  
Active Sites ◽  
Manganese Oxides ◽  
Metal Compounds ◽  
Functional Models ◽  
Current Densities ◽  
Conversion Efficiencies ◽  
Manganese Compounds

There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese–calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.

Water oxidation catalysis by manganese oxides: learning from evolution

2014 ◽  
Vol 7 (7) ◽  
pp. 2203 ◽  
Author(s):  
M. Wiechen ◽  
M. M. Najafpour ◽  
S. I. Allakhverdiev ◽  
L. Spiccia
Keyword(s):  
Water Oxidation ◽  
Manganese Oxides ◽  
Oxidation Catalysis ◽  
Water Oxidation Catalysis

scholarly journals Measurement methods of total organic carbon in seawater

2021 ◽  
Vol 233 ◽  
pp. 01078
Author(s):  
Shuwei Zhang ◽  
Zhaoyu Wang ◽  
Xuejiao Yan ◽  
Jing Wang ◽  
Li Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Water Oxidation ◽  
Combustion Method ◽  
Oxidation Method ◽  
Persulfate Oxidation ◽  
Temperature Combustion ◽  
Oxidation Efficiency ◽  
High Temperature Combustion

Total organic carbon (TOC) can reflect the total amount of organic matter in water. This paper introduces the common methods of measuring organic carbon, including high temperature combustion method, potassium persulfate oxidation method, spectrometry, ozone oxidation chemiluminescence method, supercritical water oxidation method and so on. At present, high temperature combustion method is the most widely used method for TOC measurement in seawater, because of its high oxidation efficiency. TOC sensor needs to be developed to realize in-situ and long-term monitoring.

scholarly journals Water-Oxidation Electrocatalysis by Manganese Oxides: Syntheses, Electrode Preparations, Electrolytes and Two Fundamental Questions

2020 ◽  
Vol 234 (5) ◽  
pp. 925-978 ◽  
Author(s):  
Jens Melder ◽  
Peter Bogdanoff ◽  
Ivelina Zaharieva ◽  
Sebastian Fiechter ◽  
Holger Dau ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Manganese Oxides ◽  
Catalyst Support ◽  
Catalytic Performance ◽  
Alkaline Solutions ◽  
Oxygen Evolving Complex ◽  
Conducting Oxides ◽  
First Choice ◽  
The Right ◽  
Number Of Equilibria

AbstractThe efficient catalysis of the four-electron oxidation of water to molecular oxygen is a central challenge for the development of devices for the production of solar fuels. This is equally true for artificial leaf-type structures and electrolyzer systems. Inspired by the oxygen evolving complex of Photosystem II, the biological catalyst for this reaction, scientists around the globe have investigated the possibility to use manganese oxides (“MnOx”) for this task. This perspective article will look at selected examples from the last about 10 years of research in this field. At first, three aspects are addressed in detail which have emerged as crucial for the development of efficient electrocatalysts for the anodic oxygen evolution reaction (OER): (1) the structure and composition of the “MnOx” is of central importance for catalytic performance and it seems that amorphous, MnIII/IV oxides with layered or tunnelled structures are especially good choices; (2) the type of support material (e.g. conducting oxides or nanostructured carbon) as well as the methods used to immobilize the MnOx catalysts on them greatly influence OER overpotentials, current densities and long-term stabilities of the electrodes and (3) when operating MnOx-based water-oxidizing anodes in electrolyzers, it has often been observed that the electrocatalytic performance is also largely dependent on the electrolyte’s composition and pH and that a number of equilibria accompany the catalytic process, resulting in “adaptive changes” of the MnOx material over time. Overall, it thus has become clear over the last years that efficient and stable water-oxidation electrolysis by manganese oxides can only be achieved if at least four parameters are optimized in combination: the oxide catalyst itself, the immobilization method, the catalyst support and last but not least the composition of the electrolyte. Furthermore, these parameters are not only important for the electrode optimization process alone but must also be considered if different electrode types are to be compared with each other or with literature values from literature. Because, as without their consideration it is almost impossible to draw the right scientific conclusions. On the other hand, it currently seems unlikely that even carefully optimized MnOx anodes will ever reach the superb OER rates observed for iridium, ruthenium or nickel-iron oxide anodes in acidic or alkaline solutions, respectively. So at the end of the article, two fundamental questions will be addressed: (1) are there technical applications where MnOx materials could actually be the first choice as OER electrocatalysts? and (2) do the results from the last decade of intensive research in this field help to solve a puzzle already formulated in 2008: “Why did nature choose manganese to make oxygen?”.

scholarly journals Template-free synthesis of mesoporous manganese oxides with catalytic activity in the oxygen evolution reaction

2017 ◽  
Vol 1 (4) ◽  
pp. 780-788 ◽  
Author(s):  
Suoyuan Lian ◽  
Michelle P. Browne ◽  
Carlota Domínguez ◽  
Serban N. Stamatin ◽  
Hugo Nolan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
High Activity ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Manganese Oxides ◽  
Template Free ◽  
Highly Porous

Solvothermally synthesised MnCO3 leads to template-free formation of highly porous, defect-rich MnO2 with high activity in water oxidation.

Self-healing for nanolayered manganese oxides in the presence of cerium(iv) ammonium nitrate: new findings

2015 ◽  
Vol 39 (4) ◽  
pp. 2547-2550 ◽  
Author(s):  
Mohammad Mahdi Najafpour ◽  
Maryam Khoshkam ◽  
Davood Jafarian Sedigh ◽  
Ali Zahraei ◽  
Mohsen Kompany-Zareh
Keyword(s):  
Ammonium Nitrate ◽  
Water Oxidation ◽  
Oxidation Reaction ◽  
Manganese Oxides ◽  
Concentration Profiles ◽  
Self Healing ◽  
New Findings ◽  
Cerium Iv Ammonium Nitrate

We used multivariate chemometrics methods to analyze the concentration profiles of cerium(iv) ammonium nitrate and MnO4−during the water oxidation reaction.

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